A currently available rotating electric machine with a built-in control device for onboard installation is as follows. A stator provided with coils is fixed to an inner surface of a frame. A pair of bearing brackets fixed to both sides of the frame supports a rotary shaft of a rotor via bearings. Of the aforementioned bearing brackets, the bearing bracket (rear bracket) located opposite a load side has radiating fins formed as integral parts of the bearing bracket to project from an outside surface thereof. An inverter device for operating the rotating electric machine at variable speeds is attached to the radiating fins.
A cooling fan is attached to a projecting end of the rotary shaft opposite the load side thereof, and a fan cover having an air inlet hole is attached to cover the cooling fan. There are formed ventilation openings between a peripheral part of the fan cover and a peripheral part of the bearing bracket. The cooling fan delivers cooling air to the radiating fins as a result of rotation of the rotating electric machine. The inverter device is formed into an annular shape as a whole and disposed concentrically around the rotary shaft. The inverter device includes a power unit provided with a ring-like radiating plate made of aluminum and a control circuit unit provided with a ringlike circuit board. The ring-like radiating plate is disposed on the radiating fins in a manner that enables thermal conduction, whereby heat generated by the power unit is dissipated (refer to patent document 1, for example).
Patent document 1: Japanese Patent Application Publication No. 1997-252563 (paragraphs 0015 to 0023 and FIG. 1)